As system operator, National Grid has a licence obligation to maintain a stable frequency on the electricity system to within plus or minus one per cent of 50 hertz. To be able to call on or reduce electricity generated by distributed supply sources such as wind farms, they must be able to manage input that might result in frequency variations.

"Offshore wind is one of the most flexible forms of power generation and can provide this type of service to National Grid because the output of our turbines can be rapidly and reliably adjusted to stabilise system frequency," said DONG Energy revenue and grid compliance manager, Dr. Vandad Hamidi.

"Our tests were carried out to demonstrate that offshore windfarms can provide this service reliably and flexibly. By minimising the use of more expensive alternatives, the UK's offshore wind fleet has the potential to help to save money for electricity consumers and enhance security of supply."

Richard Smith, Head of Network Capability (Electricity) at National Grid said: "We know that the future supply of energy will need to be made up of a mix of large-scale transmission power and more distributed connections linking to the grid such as the Burbo Bank wind farm. For us, these sorts of tests by suppliers are important in helping us understand the capability of the whole electricity system, and how we ensure a safe and stable supply of energy into future."

The tests was coordinated from DONG Energy's control centre, working in cooperation with National Grid's electricity control centre at Wokingham in Berkshire.

Burbo Bank offshore wind farm which has been fully operational since 2007 and is capable of supplying up 80,000 UK homes.

Notes to Editors

About DONG Energy: DONG Energy (NASDAQ OMX: DENERG) is one of the leading energy groups in Northern Europe, headquartered in Denmark. Around 6,700 ambitious employees, including over 600 in the UK, are engaged in developing, constructing and operating offshore wind farms; generating power and heat from our power stations; providing energy to residential and business customers on a daily basis; and producing oil and gas. Group revenue was DKK 71bn (EUR 9.5bn) in 2015. For further information, see
www.dongenergy.co.uk or follow us
@DONGEnergyUK on Twitter.